Double-acting two-stroke combustion engine with slot scavenging



Oct. 2-1, 1930.

H. BECKER DOUBLE ACTING TWO-STROKE COMBUSTION ENGINE WITH SLOT SCAVENGING Filed June 14, '1928 III/111111,,

Patented Oct. 21, 1930 UNITED STATES PATENT OFFICE HEINRICH BECKER, OF LAUGSBURG, GERMANY, ASSIGNOR TO THE FIRM MASCHINEN- FABRIK AUGSBURG-NUERNBERG, AKTIENGESELLSGHAF'I, 0F AUGSBURG, GER- MANY, A. CORPORATION OF GERMANY DOUBLE-ACTING TWO-STROKE COMBUSTION ENGINE WITH SLOT SCAVENGING Application filed June 14, 1928, Serial No.

en ing. %ne object of the invention is the provision of an engine of this Character having inlet and outlet openings or slots in the cylinder walls so arranged with relation to each other as to cause the resultant direction of the total stream entering the cylinder through the inlet openings to be displaced angularly in a circumferential direction from the resultant direction of the total stream leaving the cylinder through the outlet openings.

Another object of the invention is the provision of a double-acting oil engine of the character mentioned in which the inlet openings or slots are arranged unsymmetrically and in axially separated planes with respect to the group of outlet openings or slots.

Further objects andadvantages of the invention will be apparent from the following description and from the accompanying drawing, 'in which- Fig. 1 is a view in longitudinal section of one form of the invention;

Fig. 2 ,is a diagrammatic showing in section of the form of the invention illustrated in Fig. 1; I v

Fig. 3 is a perspective view of the cylinder of a modified form of construction;

Fig. 4 is a view in section corresponding to Fig. 3;

Fig. 5 is .a further form of construction illustrated in perspective; and

Fig. 6 is a sectional diagrammatic view of the invention as applied to the stufling box side of a double-acting engine.

In the construction illustrated in Figs..1 and 2 the engine is ofthe oil-injection twocycle type, Fig. 1 representing one cylinder end of a double-acting engine. The engine 1 may operate on the self-ignition. principle or in other words is of the esel type. The

cylinder walls are provided with slotted inlet-and outlet openings adapted to be opened fgand closed by t' e piston which operates lonitudinally of the cylinder. The inletand preferably arranged as" 285,435, and in Germany June 24,1927.

placed axially of the cylinder, the inlet openings or slots abeing adapted to be uncovered by the piston end after the latter has uncovered the outlet or exhaust slots by The engine is of the so-called reverse scavenging type in which the scavenging air entering the cylinder through the inlet openings at is deflected from the upper surface of the piston along the opposite cylinder wall to the cover or head of the cylinder, then back down along the cylinder wall above the'inlet openings and then toward the outlet slots. In accordance with this invention however, the reverse scavenging is such that the scavenging flow attains a speed component in a circumferential direction substantially around the cylinder axis. This whirling motion of the combustion air provides for an intimate mixture of the fuel which is injected by the usual fuel nozzle or nozzles, as shown, provided preferably in the combustion head portion of the cylinder.

The whirl of the combustion air entering through the inlet openings is attained in accordance with this invention by so arranging the inlet and outlet slots or openings through which the scavenging and combustion air flows that the resultants of the direction ofthe total stream entering the cylinder is displaced angularly in a circumferential direction from the resultant direction of the total stream leaving the cylinder. The inlet openings are preferably arranged as a group, of spaced-apart slots, these inlet slots being provided unsymmetrically with rela tion to the cylinder walls and not extending clear around the cylinder. The outlet slots are also arranged in a group unsymmetrically positioned on the cylinder walls and spaced from the inlet slotsin the direction ofthe length of the cylinder. c

As shown in Figs. 1 and2 the inlet slots extend throughout a segment of the cylinder so I as indicated between the points A and B. The

rious individual streams entering the cylin- Y der through the inlet openings a, it being understood that the various inlet openings are so directed or focused as to create a resultant flow of the total inlet stream in the direction of the line F E, displaced considerably from the medial line C D of the various inlet slots. It is apparent therefore that in this form of construction the resultant direction of the total stream entering the cylinder is in such direction as to tend to create a whirl in a counter-clockwise direction as viewed from above. The outlet slots 1) are preferably arranged in this form of construction substantially coextensive in a circumferential di rection with the extent of the inlet slots the outlet slots being so arranged as to cause the total stream of the gases leaving the cylin der to be directed through the exhaust slots in a direction which is considerably displaced from the direction of the total stream entering the cylinder. The dotted line in Fig. 1 indicates the reverse scavenging flow direc tion as combined with the whirling direction imparted to the flow in the manner just mentioned. In this manner an intimate mixture of the fuel with the combustion air entering through the inlet openings or slots a is attained and the efficiency and power of the engine is increased. It is apparent that due to the whirling action about the cylinder axis while the gases are flowing through the cylinder with the inlet and outlet slot-s open, the whirl will continue due to the inertia of the gases during the compression stroke so that when the fuel injection finally takes place the gases will still be moving about the engine axis and will flow past the injection nozzle for the efiioient utilization of the gas and fuel.

' Due to the intimate mixing of the fuel and air higher speeds of operation ofthis type of engine may be attained in an eflicient manner, and the engine is especially suitable for solid injection working. t

In the construction illustrated in Figs. 3

and 4 the inlet openings a are arranged in a group which is displaced angularly in a circumferential direction from the group of outlet openings b. Thus the inlet openings at are" provided in the cylinder wall between the points A and B and the outlet openings 1) areprovided in the segment of the cylinder walls between the points A and B. The two groups of openings are therefore unsymmetrically arranged with relation to each other; The inlet openings cause the scavenging and combustion air entering the cylinder to have a resultant direction along the line C D over the'piston head. The flow of the exhausting gases is in the direction D C, being the dividing line between the points A and B. Thus' it is apparent that the direction of the total stream entering the cylinder is displaced a considerable angle in'the circumferential diinder. The stream entering the cylinder after passing over the cylinder head in the general substantially above the inlet opening it'is" directed out of the exhaust slots I) in such a direction as to create a whirl in a counterclockwise direction .as viewed in Fig. 4,-and the flow therefore assumes a loop formation as shown in Fig. 3 to cause a continued whirl about the cylinder axis after the slots a and b are closed by the. piston, conducive to an intimate mixture of the injected fuel and the combustion air;

In Fig. 5 is shown a further form of construction which is similar tothat shown in F 3 and 4 in that the inlet and outlet openings a andb are arranged in planes displaced axially of the cylinder and arranged unsymmetrically with relation to each other so that above some of the inlet openings a, as indicated at 0, no outlet openings are provided, and below some of the outlet openings b, as indicated at (i, there are no inlet openings. The scavenging streams will therefore .enter the cylinder in a direction angularly above whichno outlet slots are provided, and

the effect of continuing or elongating the slots d under which no inlet slots are provided is to increase the angular displacement of the resultant directions of the.total inlet and outlet streams. This is true due to the fact that the extension of the slots 0 and of the slots (Z permits an increased flow through these slots, which are arranged in the greatest angular displacement with respect to each other.

Fig. 6 shows an arrangement of the scavenging and exhaust slots on the stufling box side of a double-acting machine of this character. In this form of construction, as indicated in section in this figure, the inlet slots are arranged on one side of the cylinder to create streams of scavenging air directed to each side of the piston rod, and the exhaust slots are also arranged, preferably unsymmetrically with relation to the inlet slots so that the resultant. direction of the outfiowing gases is at a considerable angle to the resultant direction of the gases flowing into the rection from the total stream leaving the cylin a circumferential III piston rod which may continue after the inlet and outlet slots are closed by the piston. The arrows shown in this figure indicate the inflowiug and outfiowing streams of gases and show how the streams whirl about the piston rod. I

\Vhile the forms of apparatus herein described constitute preferred embodiments of the invention, it is to he understood that the invention is not limited to these precise forms of apparatus, and that changes maybe made therein without departing from the scope of the invention which is defined in the append ed claims.

hat is claimed is:

1. An internal combustion engine of the two-cycle type having a cylinder provided with scavenging outlet and inlet openings provided in adjacent portions of the cylinder wall for reverse scavenging flow, a piston operating in said cylinder, the outlet and inlet openings as groups being unsyminetrical'ly arranged in a circumferential direction with relatiou to each other to cause the resultant direction of the total stream entering the cylinder through the inlet opening to be displaced augularly in a circumferential direction from the resultant direction of the total stream leaving the cylinder through the outlet openin 2. An internal combustion engine of the Diesel type having a cylinder provided with scavenging outlet and inlet openings provided in adjacent portio-ns'of the cylinder wall for reverse scavenging flow, a piston operating in said cylinder and adapted to open and-close said openings, the outlet and inlet openings as groups being arranged unsymmetrically direction with relation to each other in different but overlapping circumferential bands to cause the resultant direction of the total stream entering the cylinder through the inlet openings to be displaced angularly in a circumferential direction from the resultant direction to the total stream leaving the cylinder through the outlet open- 1ng.

3. An internal combustion engine of the Diesel type having a cylinder provided with outlet and inlet openings and a piston operating in said cylinder, the outlet and inlet openings groups being arranged unsyminetrically in a circumferential direction with relation to each other to cause the resultant direction of the total stream entering the cylinder through the inlet openings to be displaced angularly in a circumferential direc-' tion from the resultant direction of the total stream leaving the cylinder through the outlet openings for the creation of a whirling action of the gases about the cylinder axis.

4. An internal combustion engine of the two-cycle type having a cylinder provided with scavenging outlet and inlet openings provided in adjacent portions of the cylinder ing the cylinder-through the inlet openings to be displaced angularly in a circumferential direction from the resultant direction of the 'total stream leaving the cylinder through the outlet openings.

5. A double-acting engine; of the two-cycle type operating with fuel'injec tion having a cylinder provided with scavenging outlet and inlet openings provided in adjacent portions of the cylinder; wallfor reverse scavenging, a piston operating in said cylinder and cooperating with said outlet and inlet openings to open and close the same, there being a group of spaced inlet openings provided in an-unsymmetrical manner in the cylinder walls and a group of outlet openings provided in an unsymmetrical manner in the cylinder Walls the tWo groups being arranged unsymmetrically-in' circumferential directions with re-' spect to each other and in axially separated planes to cause the resultant direction of the total stream entering .the cylinder through the inlet openings to be displaced angularly in a circumferential direction from the resultant direction of the total stream leaving the cylinder through the outlet openings for the creation of, a whirling action of the gases about the cylinder axis, the group of inlet openings containing some which are elongated in the direction of the cylinder length, and the group of outlet. openings containing some which are elongated in the direction of the cylinder length, the elongated inlet openings being elongated toward the plane of the outlet openings and the elongated outlet openings extending toward the plane of the inlet openings. 7

In testimony whereof I have afiixed my HEINRICH BECKER.

sign ature.

CERTIFICATE OF CORRECTION.

Patent No. 1,779,112. Granted October 21, 1930, to

HEINRICH BECKER.

It is hereby certified that the name of the assignee in the above numbered patent was erroneously written and printed as "Maschinen-Fabrik", whereas said name should have been written andprinted as "Maschinenfabrik", as shown by the records of assignments in this office; page 3, line 43, claim 2, for "openings" read opening, and line 45, same claim, for "to" read of; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

. Signed and sealed this 9th day of December, A. D. 1930.

M. H. Moore, (Seal) Acting @ommissioner of Patents. 

